Rotary file



s. T. FREAS 2,098,865 4 ROTARY FILE Nov. 9, 1937.

Filed Feb. 12, 19:57 I 3 Shets-Sheefc 1 S. T. FREAS Now 9, 1 93 FiledFeb. 12, 1937 s Sheets-Sheet 2 S. T. FR EAS Nov. 9, 1937.

ROTARY FILE 3 Sheets-Sheet s Filed Feb. 12, 1957 Patented Nov. 9, 1937UNITED STATES PATENT OFFECE.

ROTARY FILE Application February 12, 1937, Serial No. 125,510

2 Claims.

This invention relates to improvements in rotary files, and moreparticularly in files of the type used for sharpening beet knives inaccordance with the general principles set forth in United States PatentNo. 2,069,140, dated January 26, 1937.

The prior form of rotary file used to form the bevels at the cuttingedges of beet knives has been relatively ineificient by reason ofinability to stand up under normal working conditions, and a principalobject of the present invention is to provide a rotary file of novelform having a considerably longer useful life than the prior files ofthe same class, and which shall be capable of a' relatively extendedcontinuous use in the filing operation.

Another object of the invention is to provide a file that shall be moreefiicient in operation and capable of producing generally improved andmore precise results.

In the attached drawings:

Figure 1 is a sectional perspective View of a file made in accordancewith my invention;

Fig. 2 is an enlarged fragmentary sectional view of the file;

Fig. 2a, is an enlarged fragmentary sectional view illustrating a fileof modified form and characteristics;

Fig. 3 is a view in perspective of a beet knife of conventional form;

Figs. 4, 5 and 6 are more or less diagrammatic views illustrating themanner in which the beet knife is presented to the file in thesharpening operation, and

Figs. '7, 8, 9 and 10 are fragmentary sectional views illustrating thevarious operations of the sharpening process.

With reference to Figs. 1 and 2 of the drawings, a file made inaccordance with my invention comprises principal filing surfaces l and2, the surface I being formed on one side face of the blade 3, and thesurface 2 being formed at the beveled periphery of the blade andextending at an angle to, and constituting in effect a continuation of,the surface The angular relation between the surfaces 5 and 2 may vary,the standard included angle between these surfaces being 50, and inpractice it is customary to furnish these files with bevel angles ofboth 50 and 45. Other angles may be used without departure from theinvention.

In accordance with my invention, Iprovide a third filing surface 4 whichis formed on a reverse bevel extending from the outer end edge of thefiling surface 2, and the included angle between the bevel surface 4 andthe adjoining face 5 of the blade 3 is'greater than the included anglebetween the filing surfaces l and 2. Where the latter angle is 50, theincluded angle between the filing surface 4 and the adjoining face ofthe blade may suitably be in the neighborhood of 40. It will be notedthat the aforedescribed construction provides a continuous filingsurface embracing the adjoining angularly disposed surfaces l, 2 and 4.

The invention resides in the provision of the filing surface 4.Heretofore it has been customary to produce these knives, as illustratedin Fig. 2a, with only the filing surfaces la. and 2a, corresponding withthe surfaces l and 2 described above. In this case also, the sidesurface 511 at the opposite side of the blade 30. from the filingsurface la extends fiatly to the outer edge of the filing surface 2a. Asset forth above, files of this prior character tend to deterioraterelatively rapidly in use. I have discovered that by providing theadditional filing surface 4, as described above, the characteristics ofthe tool as to durability, and, also in certain other respectshereinafter set forth, are materially improved.

The function and mode of operation of the file, and specifically of thesupplemental filing surface 4, will be more readily understood from aconsideration of the other figures of the drawings. In Fig. 3, I haveshown a beet knife of conventional form comprising the typical V- bottomchannels 6, the sides of which are formed by the splitter blades 1. Theouter end edges of the splitters I are beveled as indicated at 9 toproduce the sharp cutting edges of the splitter elements, and it is thefunction of the filing surface I of the file to produce these bevels, itbeing understood that rightand left-hand files are provided to form thebevels at the respective opposite sides of the splitters. The end edgesof the V-shaped bottoms of the channels 6 are correspondingly beveled,as indicated at H], and these bevels are produced by the filing surface2 of the file. With a file made in accordance with my invention, thecuts on each bevel 9 and the adjoining bevel ID are made in a singlepass of the file, two operations, performed respectively by the rightandleft-hand files, being required to form the bevels 9 and Ill on oppositesides of each channel.

In filing the bevels, a relationship between the file and the beet knifesuch, for example, as shown in Figs. 4, 5 and 6, is maintained. In afiling machine of the character disclosed in the aforesaid United Statespatent, the beet knife to compensate a slight taper in the splitters 1.

' from their bases toward their tops,'see Fig. '7,

, adjoining bevel II] on the contiguous side'of V of the channel 6, asshown in Fig. 10, the filing and this angular relation is indicated at bin' Fig. 6. r

In Fig. 8, I have illustrated the relative posi: tions of the file andthe beet knife in, cutting the bevels 9 on one'side of a. splitter 1and'the the Vbottom 8, it being noted that the two bevels are formedsimultaneously by the filing surfaces I and 2, of the file Fig.'7"sliows=the end edges of the blade prior'to the filing operation, and Fig.9 the same edges subsequent to the filing operation illustrated inFig.8, Inthis 7 latter figure, it will be'noted that in addition tothe'bevel's on the splitter l, and the bevel ID at one side of theV-bottom 8, an additional bevel cut l2 is produced on the oppositelyinclined side of the v bottom by the filing surface-4 of ithe file. Whenin a subsequent operationthe bevels l8 and 9 are produced at theopposite side surface 4 of the file used in that operation does notfunction, since by reason of its angular posi- .;tion in the file, itfails to contact the opposite and previously formed bevel surface ID.

The dilficulties that have been-experienced with the. form of file,illustrated in Fig. 2, arise from thefact that in that case the extremeperipheral edge of the file at the outer end of the filing sur:

face 2a, being attenuatediand relatively weak, was unable adequately .tosupport the imposed.

load. Furthermore, the conditions under which this part of the file wasrequired to operate,

without relief in the angle of the V-shaped bot-' toms of the channels,imposed exceptional loads tendency toward deflection. the file is, thus,materially extended, and the upon this relatively weak part. This wasmani-.

fested by a tendency of the narrow peripheral rim of the file to bind inthe work. These prior files also exhibited a tendency to deflect'fromtheir normal path in the 'work, with resulting slight inaccuracies ofout. As a result of these conditions, the files in operation exhibitedrapid deterioration at the periphery, and their useful life wascorrespondingly limited. I

In files made in accordance with my invention, all portions of thefiling surfaces operate under fully relieved conditions. Specifically,the

presence of the filing surface 4 functions to relieve the attenuatedperipheral rim portion. Not only is all tendency of this portion of thefile to bind in thework avoided, but the file shows no The useful lifeof precision characteristics substantially improved. I claim: V a V V 1.A rotary file for sharpening beet knives and the like, said filecomprising a circular diskblade.

having in the peripheral portion thereof a ra--- dially disposed filingsurface, a beveled filing surface adjoining the outer edge of saidradial surface and extending at a predetermined angle.

to the latter, the outer. edge of said bevel surface forming the extremeperiphery of the blade, 1 and a reversely beveled filingsurfaceextending from said extreme periphery.

2. A rotary file for sharpening beet knives and the like, said filecomprising a circular disk blade having in'the peripheral portion.thereof a ra-' dially disposed filing surface, a beveledfiling surfaceadjoining the outer edge of said radial surface and extending at apredetermined angle to the latter, the outer edge of said .bevelsurfaceforming the extreme periphery of the blade, and

a reversely beveled-filing surface extending from said extremeperiphery, the last-named surface forming with a radial planeintersecting. the said extreme periphery an acute angle less than theacuteangie formed, between said plane and the first-named bevel surface.

sAM EL fT; FREAS;

